One vertex per element, one color per generator, with an edge from x to x·s.
(1,2,5,8)(3,7,4,6)(9,10,13,16)(11,18,19,15)(12,14,17,23)(20,22,21,24)(25,26,31,35)(27,32,33,39)(28,38,40,37)(29,34,30,36)(1,3,5,4)(2,6,8,7)(9,11,13,19)(10,15,16,18)(12,22,17,24)(14,20,23,21)(25,27)(26,32)(28,34)(29,37)(30,38)(31,33)(35,39)(36,40)(9,12,14,16,13,17,23,10)(11,15,20,22,19,18,21,24)(25,28,30,32,31,40,29,39)(26,33,34,38,35,27,36,37)(1,4,5,3)(2,7,8,6)(10,16)(12,17)(15,18)(22,24)(25,29,31,30)(26,34,35,36)(27,37,33,38)(28,39,40,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.